Strongly coupled phase transition in ferroelectric/correlated electron oxide heterostructures

TL;DR

This study demonstrates that ultrathin ferroelectric/correlated electron oxide heterostructures can exhibit a strongly coupled insulator-metal transition driven by ferroelectric field effects, with significant changes in electronic and magnetic properties.

Contribution

It provides experimental evidence of strong ferroelectric field effect control in ultrathin heterostructures, enabling large resistivity modulation and coupled electronic-magnetic phase transitions.

Findings

Achieved at least a 100,000-fold change in resistivity.

Observed a thickness-dependent insulator-metal transition.

Demonstrated coupling between ferroelectric field effect and magnetic properties.

Abstract

We fabricated ultrathin ferroelectric/correlated electron oxide heterostructures composed of the ferroelectric Pb(Zr0.2Ti0.8)O3 and the correlated electron oxide (CEO) La0.8Sr0.2MnO3 on SrTiO3 substrates by pulsed laser epitaxy. The hole accumulation in the ultrathin CEO layer was substantially modified by heterostructuring with the ferroelectric layer, resulting in an insulator-metal transition. In particular, our thickness dependent study showed that drastic changes in transport and magnetic properties were strongly coupled to the modulation of charge carriers by ferroelectric field effect, which was confined to the vicinity of the interface. Thus, our results provide crucial evidence that strong ferroelectric field effect control can be achieved in ultrathin (10 nm) heterostructures, yielding at least a 100,000-fold change in resistivity.